1. Field of the invention
The present invention relates to an improvement on a lock structure, more particularly one, which includes a lock body, and a locking crutch to cooperate with the lock body to lock an object; the lock body is equipped with two movable engaging plates, and the locking crutch has two grooves to receive respective ones of the movable engaging plates so that the lock can be firm in the locking configuration.
2. Brief Description of the Prior Art
A variety of locks are available for helping to prevent thievery, e.g. door locks, combination locks, and cable locks, which are mainly used for locking bicycles and motorcycles. And, the industry have recently developed electromagnetic locks, chip locks, and voice-controlled locks, which are more advanced than the above-mentioned conventional locks, and can't be easily opened by unauthorized persons. Moreover, stronger locks are also available, which are made of saw-resistant materials so as not to be damaged with saws.
A currently existing saw-resistant lock is available, which includes a lock body consisting of several metallic plate parts. The plate parts have already undergone heat treatment to increase their strength, and are positioned on above another. Therefore, it is relatively difficult for thieves to damage the lock with a saw.
However, it takes relatively much cost, labor and time to manufacture the saw-resistant lock because all of the metallic plate parts have to be subjected to heat treatment, and then stacked and fastened together by means of rivets.
To overcome the above-mentioned problems, the inventor of the present invention developed an improvement on a saw-resistant lock, which has been filed for U.S. patent application with application Ser. No. 11/979,652. The saw-resistant lock includes a lock body, a lock core held in a core holding hole of the lock body. The lock body has several pin holes on a periphery portion thereof, and saw-resistant pins are inserted in the pin holes of the lock body respectively; the saw-resistant pins have already undergone heat treatment to have high strength. Therefore, the present lock has a lower manufacturing cost, and is easier to assembly than the above-mentioned saw-resistant stacked-plate lock.
However, besides having saw-resisting capability, a lock should be very firm in the locking configuration and smoothly operable without the possibility of its locking crutch being interfered with when moving relative to the lock body. Therefore, it is a main object of the present invention to provide an improvement on a lock, which has a good saw-resisting capability, and is smoothly operable, and relatively easy to assemble as compared with the above-mentioned saw-resistant stacked-plate lock.